During burn-in testing, it is desirable to designate a single chip output for monitoring purposes. When burning in multiple complex Intellectual Property Modules (IP modules), provision of this capability typically requires the construction of an OR tree of the monitor outputs from each module instance. Whilst not difficult, this is an irregular structure, implementation of which requires time and effort that could be better spent elsewhere. Customers are often reluctant to do this, and so monitoring is often not available.